Response to Randall A & Larner AJ. Primary progressive aphasia: misdiagnosis with ‘normal’ imaging

Abstract

Progress in Neurology and PsychiatryVolume 24, Issue 4 p. 31-31 LettersFree Access Response to Randall A & Larner AJ. Primary progressive aphasia: misdiagnosis with ‘normal’ imaging First published: 09 November 2020 https://doi.org/10.1002/pnp.686AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Randall and Larner1 are right to draw attention to the fact that the syndromes of primary progressive aphasia (PPA) remain unfamiliar to some clinicians. One reason is the ‘Black Magic fallacy’ – the assumption that understanding a disorder requires a highly specialised skill set. The cases presented highlight three others: the omission from standard clinical assessment of a simple test of motor speech (the ‘pataka test’); failure to appreciate the significance of subtle radiological changes such as asymmetric widening of the sylvian fissure, and the assumption that a speech/language disorder is a sign of vascular pathology. We agree that a structured clinical approach to the suspected involvement of language in a patient presenting with cognitive change could help both in overcoming barriers to the thorough assessment of patients presenting to memory clinics and in improving clinicians’ awareness of this group of disorders. In this context we were pleased to see reference to the preparation of ‘a mini linguistic state examination (MLSE)’. We have recently completed a thorough validation of this instrument in a cohort of 54 patients meeting the accepted criteria for the three main variants of PPA (authors’ Table 1).2 Although scoring of the test – which relies on the recognition of error types rather than a simple summation of correct responses – may at first seem unfamiliar, administration of the MLSE is not much more time consuming than an MMSE or MoCA, and should be able to be accommodated within a standard clinic assessment. A paper reporting the diagnostic properties of the test is currently under review, with a preprint available at www.medrxiv.org/search/MLSE. Our results suggest that the application of a few rules to classify errors across a series of simple linguistic assays (which include the ‘pataka’ test) can support rapid and confident diagnoses of semantic variant, nonfluent variant and logopenic variant PPA (svPPA, nfvPPA and lvPPA). Moreover, patients who do not fall neatly into one of these categories (‘mixed’ PPA)3 can be described, rather than omitted because the nature of their deficit is not cleanly captured by the ‘paradigm syndromes’ heuristic. The MLSE has been validated not only in English (including a cultural adaptation suitable for use in North America) but also in Italian and Spanish. Work on the more challenging modifications required to achieve equivalence in languages outside the Indo-European family is shortly to commence. The MLSE is free to use for clinical purposes, and the test can be downloaded from http://mlsexam.com on completion of a series of brief introductory tutorials. We hope that incorporation of the test in memory clinic assessments will lead to wider recognition of this group of disorders, encouraging and enabling the development of cohort-based research that will be essential to the evaluation of future therapeutic interventions. Professor Peter Garrard PhD, FRCP, Professor of Neurology, Dr Nikil Patel PhD, Research Fellow in Neuroscience, Molecular and Clinical Sciences Research Institute, St George's, University of London; Professor James Rowe PhD, FRCP, Professor of Neurology, Professor Karalyn Patterson PhD, FRS, FBA, FMedSci, Emeritus Professor, Dr Katie Petersen PhD, Research Fellow in Neuroscience, Cambridge University Department of Clinical Neuroscience, Cambridge; Professor Stefano Cappa MD, Professor of Neurology, University School for Advanced Studies (IUSS-Pavia), Italy, and Prof Matthew Lambon Ralph PhD, FBA, Director, MRC Cognition and Brain Sciences Unit, Cambridge. Declaration of interests No conflicts of interest were declared. References 1Randall A, Larner AJ. Primary progressive aphasia: Misdiagnosis with ‘normal’ imaging. Progress in Neurology and Psychiatry 2020; 24:2: 11– 13. Wiley Online LibraryWeb of Science®Google Scholar 2Vandenberghe R. Classification of the primary progressive aphasias: principles and review of progress since 2011. Alzheimers Res Ther 2016; 8: 16. PubMedWeb of Science®Google Scholar 3Grossman M. Primary progressive aphasia: clinicopathological correlations. Nat Rev Neurol 2010; 6: 88– 97. CrossrefPubMedWeb of Science®Google Scholar Volume24, Issue4October/November/December 2020Pages 31-31 ReferencesRelatedInformation